Multiple electrode radiotron



May 10, 1932. A. B. DU MONT- ET AL MULTIPLE ELECTRODE RADIOTRON Original Filed May 20, 1924 a J f m A mm mmwflc cw fi||||||| G. $55M LI... 6% F 2 2 u a I ELEFEEF G 5...? F X 0 0% o 2 8 M 4 k 3 HEP. i 5 PLLEMMMBWW ull :ll 3---- F INVENTOR All! 5. DuMmvT PAUL T. Pvt K5 ATTORNEY Patented May 10, 1932 UNITED STATES PATIENT. OFFICE;

ALLEN B. DU MONT, OF IlllIION 'IlCIIAZIIIRI, AND PAUL THORNE WEEKS, OI CALDWELL, NEW

JERSEY, ASSIG-NORS T WESTINGHOUSE LAMP COMPANY, ,A CORPORATION OI PENNSYLVANIA MUL'I'IELE ELEO'IRQDE RADIOT'RON- Application filed May 20, 1924, Serial No. 714,542. Renewed Augultl, 1930.

This invention pertains to systems for the amplification of energies and more specifically to electronic methods of amplification and apparatus therefor.

B It is an object of the invention to provide an electron-emitting apparatus superior to constructions now in use.

It is another object of the invention to provide apparatus of the character specified that may be used for both radio-frequency and audio-frequency amplification in a suitable system.

It is a further object to combine in a single vacuum tube device, a plurality of arrange- 16 ments or apparatus for performing a plurality of functions heretofore requiring separate devices.

It is a still further object of the invention to eliminate the difiiculties arising from difference in degree of vacuum as between several thermionic devices as heretofore employed in one system.

Yet further objects are to provide a device such as a radio tube that will be simple and cheap of construction, eflicient and reliable of operation, that may have substantially twice the life of any tube now in use and one that will have certain novelties of construction and function that have not heretofore been obtained and as will more particularly appear from the description and claims and from the drawings in which;

Fig. 1 is a side elevation of one form of electrode mount including the stem flare constructed in accordance with our invention;

Fig. 2 is a top plan view taken along the line 11-11 of Fig. 1;

Fig. 3 is a view similar to that of Fig. 1 of a different form embraced by our invention;

Fig. 4 is another view similar to Fig. 1 of astill further form of our invention; and,

Fig. 5 is a view of Fig. 4 taken along the line VV of Fig. 4.

In an application filed by Siegmund Loewe, August 26, 1921, Serial No. 495,777, entitled Multiple boosters or multiple vibration generators and assigned to the Westinghouse Electric & Manufacturing Company, a multi- 50 ple electrode electronic device is described and claimed, and whilea tube constructed in accordance with the teaching of said application is most desirable and has excellent qualities, many difficulties may be encountered in its construction. By our invention, we overcome those difficulties and provide an economical and efficient device.

It will be readily appreciated that in order to obtain the minimum plate resistance or the minimum space charge effect, it is essentialin radio tube construction to have the average distance from plate to filament as small as possible and to provide a filament of great length. It will also be evident that if-for mechanical reasons the plate-filament distance cannot be less than a certain value, the first condition will be entirely fulfilled by a cylindrical plate and that if the filament cannot be greater than a certain length, the use of two or more filaments or cathodes is advantageous. Such a construction would make it possible to use a length of filament greater than could be supported in a singlestrand without the addition of center or other supports and at the same time a length of filament that will permit the use of those voltages and currents for a temperature at which suitable electron emission and long life are obtained.

Referring to the drawings, a stem 2 carrying leads 4, 6, 8, 10, 12 and 14 through press 16 together with the electrodes hereinafter described, constitutes the mount of one form of my invention. The leads 4, 6, 8, 10, 12 and 14 may constitute the supports for the 85 electrodes in addition to performing their function as leads, although they may be connected as shown in the figure to electrode supporting and conducting members in any suitable manner. Thelead 10 is connected to a supporting member 18 which passes up through the center of a neck 20, connecting together, two cylindrical portions 22 and 24 of a plate electrode or anode, and serves to support said plates. This neck portion 20 may be integral with the plates as shown or may be formed in any other suitable manner. Preferably positioned within the cylindrical portion constituting the anodes are the grids or space current controlling electrodes 26 and 28, which are mounted upon separate and unitary supports 30 and 32 respectively, which may extend the whole length of the grid. The third electrode element of the tube comprises the filaments or cathodes 34 and 36, which extend through the centers of the grids between a support formed by portion 38 at right angles to a supporting lead 40, and individual supporting leads 42 and 44 to which they are respectively secured, the supporting leads being sealed into the press 16. The plates and grids are arranged concentricallyabout the filaments as will be noted in Fig. 2. In this construction,the leads 4, 8 and 12 serve thetwo filaments 34 and 36 and by appropriate connections the two filaments may be operated in parallel, in series, or individually as may be desired.

The construction shown in Fig. 3 does notdifler materially from that shown in Fig. 1 except that the filament-s are supported by a horizontal support 46 which is attached to the plate support 18 by means of a glass or other insulating head 48. In this construction the filaments may be burned only in series but in both the construction of Fig. 1

and that of Fig. 3, the two grids may be used independently as, for instance, in cases where one grid is used for controlling radio-frequency amplification and the other for controlling audio-frequency. amplification.

The construction shown in Fig. 4 can be best understood by reference to Fig. 5 in which it will be noted that a support 18", in this case supports the two grids by passing through a mid web portion 19 thereof while the double barrelled plate or anode 2224 is supported by means of supports 50 and 52. Various other modifications may be made but for the sake of convenience we have illustrated only three.

lVith the constructions described, i. e., with the electrodes concentric and substantially surrounding one another, it has been found practical to obtain a plate resistance as low as 8,000 ohms as compared to a plate resistance of 10,000 ohms with the common form of rectangular plate-filament distance. the same value of amplification constant being obtained in the two cases. It therefore follows as a corollary and actually works out in practice, that this construction makes it possible to obtain a higher amplification constant with the same value of plate resistance. Tubes made in accordance with the invention and used in a radio system give greater amplification and less distortion.

Various modifications of the construction may be made without departing from the spirit of the invention or the termsof the claims hereinafter appended. I

What is claimed is:

1. In a vacuum tube, a compound anode of sheet material comprising a plurality of hollow cylindrical portions and a double- 3. In a thermionic tube, a compound elec.

trode of sheet metal comprising a plurality of cylindrical portions interconnected by a double-wall web portion extending substantially parallel to the axes of said cylindrical portions, and a .supporting element aflixed to said double-wall portion.

4. In a thermionic tube, a compound electrode of sheet metal comprising a plurality of cylindrical portions interconnected by a double-wall web portion extending substantially parallel to the axes of said cylindrical portions. a part of said double-wall portion being modified to accommodate a supporting element, and a supporting element aflixed to said modified part.

5. In a thermionic device, a compound electrode of sheet metal comprising a plurality of cylindrical portions interconnected by aweb portion integral therewith, said web portion being channeled to receive a supporting element, and a supporting element disposed within said channel.

, 6. In a vacuum tube, a cathode, a compound anode of sheet material comprising a plurality of hollow cylindrical portions and a double-Wall constricted connecting portion.

7. In a vacuum tube, a cathode a compound anode of sheet material comprising a plurality of hollow cylindrical portions and a double-wall constricted connecting portion, and a substantially cylindrical grid in each of said cylindrical portions.

8. In a Vacuum tube, a cathode, a compound anode of sheet material comprising a plurality of hollow cylindrical portions and a double-wall constricted connecting portion, and a substantially cylindrical grid in each of said cylindrical portions, said cylindrical grids being connected by a double-wall connecting portion.

9. In a vacuum tube, a cathode, a compound anode of sheet material comprising a plurality of hollow cylindrical portions and a double-wall constricted connecting portion, and a substantially cylindrical grid in each of said cylindrical portions, said cylindrical grids being connected by a double-wall connecting portion, and a support for said grids attached to said last mentioned double-wall connecting portion.

10. A vacuum tube containing a plurality of substantially cylindrical anode portions, substantially cylindrical grid portions inside of said anode portions, and cathode portions inside of said grid portions, said anode portions having a double-wall connecting portion, said grid portions having double-wall connecting portions.

11. A vacuum tube containing a plurality of substantially cylindrical anode portions, substantially cylindrical grid portions inside of said anode portions, and cathode portions inside of said grid portions, said anode portions having a double-wall connecting portion, said grid portions having double-wall connection portions, said anodes being connected to each other.

12. In a vacuum tube, a compound grid comprising a plurality of hollow cylindrical portions and a double-wall connecting portion of less diameter than said cylindrical portions.

13. In a vacuum tube, a compound grid structure comprising a plurality of cylindrical portions, a double-Wall connecting portion and a supporting member enclosed by the walls of said connecting portion.

-In testimony whereof, we have hereunto subscribed our names, this 8th day of May, 1924, and this 13th day of May, 1924:.

ALLEN B. DU MONT.

PAUL THORNE WEEKS. 

